Séminaire Lotharingien de Combinatoire, B75f (2016), 12 pp.
Xin Fang and Ghislain Fourier
Torus Fixed Points in Schubert Varieties and Normalized Median Genocchi Numbers
Abstract.
We give a new proof for the fact that the number of torus fixed points
for the degenerate flag variety is equal to the normalized median
Genocchi number, using the identification with a certain Schubert
variety. We further study the torus fixed points for the symplectic
degenerate flag variety and develop a combinatorial model, symplectic
Dellac configurations, to parametrize them. The number of these
symplectic fixed points is conjectured to be a median Euler number.
Received: January 1, 2016.
Revised: May 25, 2016.
Accepted: May 25, 2016.
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